Web feeding mechanism for photographic apparatus and the like



Feb. 17, 1953 J. F. CRAIB v 2,628,834

WEB FEEDING MECHANISM FOR PHQTQGRAPHIC APPARATUS AND THE LIKE. Filed May3, 1948 3 Sheets-Sheet l xiL...

I 1 :I- ::l i T- r5 I INVENTORZ w Llirraes Feb. 17,1953 J. F. CRAIB2,628,834

WEB FEEDING MECHANISM FOR PHOTOGRAPHIC APPARATUS AND THE LIKE Filed May3, 1948 3 Sheets-Sheet 2 2 IN V EN TOR.

cZinzesZ'CrazZ Patented Feb. 17, I953 WEB FEEDING MECHANISM FOR PHOTO-GRAPHIC APPARATUS AND THE LIKE James F. Craib, Town of Gates, N. Y.,assignor,

by mesne assignments, to Bell & Howell Company, Chicago, Ill., acorporation of Illinois Application May 3, 1948, Serial No. 24,734

4 Claims.

The present invention relates to web feedin and conveying and moreparticularly to the driving of a continuous web product through a liquidbath or baths or otherwise conducting its progress while in a saturatedcondition and it has for its general object to provide a simple, durabland effici'ent apparatus for accomplishing this purpose in a mannerwhereby the web is caused to advance at a, uniform rate at all stagesand throughout its length even though, in the meantime, it may 'beeither shrinking or stretching.

'A further object of the invention is to provide such an apparatus thatwill be capable of feeding a plurality of continuous webs together andside by side over and through the same conducting means with a desireduniform tensile strain on each and all even though the degree of linearexpansion and contraction on the part of the individual webs may varyunder the same treatment.

A still further object of the invention is to accomplish these resultsby means of a direct frictional drive against the surface of the webitself by devices that also support it in taut stretches and stillcompensate for linear variations. 7

These and other desirable objects are accomplished by the constructiondisclosed as an illustrative embodiment of the invention in thefollowing description and in the accompanying drawings forming aparthereof, in which:

Fig. 1 is a fragmentary side elevation of the entry end of a webtreating and feeding machine constructedin accordance with andillustrating one embodiment of this invention;

Fig. 2 is a vertical section on the line 22 of Figfil looking in thedirection of the arrows;

'Fig. 3 is a fragmentary top plan view of the.

motorgearing for the chain drive of the web feeding mechanism;

Fig. 4 is a fragmentary, vertical section on the line 44 of Fig. 3;

Fig. 5 is a detail cross section of one of the feed rolls or units;

.Fig. 6 is a diagrammatic end view of a feed unit and a web fragmentengaged therewith, illustratin'g thecompensating behavior of the latterunder one condition; and

Fig. 7 is a similar view illustrating the behavior 2 chine. In thedeveloping, washing, and fixing operations of such a machine it isfrequently desired to runa plurality of coated paper websside by side invertical loops through successive baths to the final drier. As the paperbecomes more and more saturated it stretches progressively and yet it isdesired that the reaches of the loops between upper and lower supportsbemaintained gently taut so that they may be run compactly closetogether and yet not interfere or touch each other. Obviously the wholelength of wet web cannot be drawn through the machine by its advancingend, yet that end must. travel more rapidly than the initial feed end.when the film is dry because the film, with saturation, stretchesprogressively as it advances and. is longer when it emerges than when itenters the machine. If the feeds were the same the extra length wouldaccumulate in the tanks, causing a confused disposition of the reachesof the loops, resultin in undesirable contacts and other complications.With the present invention the feeding impulses communicated to the filmor Web increase progressively yet automatically at successive loopsupports according to the tension on the web so that just enough tensionis maintained and the reaches or falls of the loops in the liquids aremaintained flat and out of contact with each other. Yet this is donewithout the use of any differential speed driving mechanism, which wouldbe complicated and expensive.

Referring more particularly to the drawings, wand 12 indicate the upperand lower rails of a supporting frame 14 for tanks l6 and I8, the formerof which is the initial receptacle and the latter of which, partlyshown, is one of a continuing series. 'Ihese tanks rest on bottom crossrods 20 at the rails. l2. 'l'ank i6 is jacketed and there are otherformations such as partitions 22, 24, and 26 Which divide the first tankinto three bath compartments and the second into two, but such mattersare immaterial to the present invention. A liquid level shown in Fig. 2is mamtained by suitable overflow connections 28.

Secured to the upper rails III at 30 and connected below at 32 aredepending hangers 34 carrying, bearings for a horizontal series ofequally spaced, parallel idle rolls 3% near the bottom. of each tank.The upper rails Ill provide bearings 38 for a coextensive series ofdrive rolls 40 also horizontally arranged, the projecting ends of theshafts 42 of which are housed within the rail channels by cover plates44. One set of these shaft ends are provided" with sprockets 46 over allof which runs a I sprocket chain 48 so that all of the feed rolls aredriven together at a uniform rate.

The webs W of film or paper (usually the latter, in the preferred use ofthe machine) are drawn from a suitable source, such as a supply reel(not shown) and enter the apparatus from the left of Fig. 1 over a guideroll 50 and then pass between an initial smooth-surface feed andmetering roll 52 which is positively driven, and its associated contactroll 54 which is an idler roll. Two or more separate webs may be fedthrough the machine at the same time, three being here shown as anexample. After passing the feeding and, metering rolls 52, 54, theythence are looped back and forth between the further feed or impellingrolls 40 at the tops and the idle rolls 36 at the bottoms of the tanksso that their reaches are fiat, substantially paral lel, and as closetogether as is feasible with respect to the nature of the baths throughwhich they thus pass. The initial feed roll 52 is driven at a suitablespeed by a motor 56, belt 58, reduction gearing B0, and a coupling 62 onthe shaft 64 of this roll. The other feed rolls 40 are all driven at thesame rotary speed by the chain 48 which passes over and is driven by asprocket on the shaft 64, and which in turn drives all of the sprockets46 on the shafts 42 of. the rolls 40.

The driving and repeated immersions of the web through the various bathsis a usual procedure with ordinary feeding and impelling rolls in. theposition of the present rolls 40. With the usual equipment, however, andas first explained, the webs in a photographic developing machine, atleast, are dry at the initial roll 52 but, before they have progressedfar they increasingly stretch or expand so that there is a greaterlength of web to be fed out of the exit end of the machine than the.length of web introduced into the entrance end.

In the practice of the. present invention, this increasing length of theweb is accommodated by constructing the individual feed rolls in amanner best shown in Figs. 2, 3,. and 5 to 7. They are preferably ofpliable rubber and their only contact with the film web istaken by aplurality of longitudinally extending tapered ribs 66. project roughlytangentially from the main body of the-roll and which are relativelyeasily'bendable and resilient laterally, toward and away from theirshafts 42 When viewed in cross section as in Fig. 5, it is seen that thecentral plane or median plane of each rib is roughly tangential to thebasic diameter of the roll; that is, the diameter of the part of theroll between successive ribs. The rolls are driven in the direction ofthe arrows in Figs. 6 and '7, and the ribs extend obliquely in atrailing direction rather than a leading direction, as is seen fromthose figures.

The ribs tend resiliently to expand to their initial or undeformed shapeshown in Fig. 5, but any substantial tension or tautness in the webpassing over a roll will cause the ribs on that roll to bend inwardly toa greater or lesser extent (depending on the degree of tension) asindicated diagrammatically in Fig. 6, thus decreasing the effectivediameter of that roll and slowing, down the rate of feeding the webpast. that. roll until the tension on the web is decreased; (by reasonof. the slowing; down of the feed), whereupon the ribs: may be able toexpand. outwardly somewhat. Thus. these. feed rolls 40 automaticallyvary their effective diameters (and thus their feeding speeds) inaccordance with the tension or tautness of various portions of the webpassing over the various successive feed rolls.

An important feature of this invention is the relation of diameter ofthe metering roll 52 to the diameters of the feed rolls 40. Thesmoothsurface metering roll has a diameter which is substantially lessthan the maximum effective diameter of the feed rolls 40 when their ribs66 are fully extended to their normal undeformed shape, but slightlygreater than the minimum efiective diameter of the feed rolls when theirribs are fully folded over as far as they will fold or compress as aresult of a reasonable degree of tension within the strength limits ofthe paper or other web material. Hence when a web is introduced into themachine, the first few feed rolls 40 will immediately try to feed theweb faster than the metering roll 52 will allow it to travel, so that atension will immediately be created, which will deform or bend over theribs 66 on the first few feed rolls 40 until their effective diametersand feeding speeds are equal to those of the metering roll 52. The ribson the first few feed rolls will be in approximately the positionsillustrated in Fig. 6.

As the web progresses through the machine, however, and becomesincreasingly saturated by the liquid baths, it expands in length, whichdecreases the longitudinal tension in the web, which in turn allows theribs to expand to increase the effective diameter of the feed rolls overwhich the web passes after such expansion, so that the rollsautomatically accommodate themselves to the increasing length of the weband will properly feed the web out of the machine without allowing anyaccumulation of slack in the machine, even though the length of. the webas it issues from the machine is greater than the length of the web asit is fed into the machine.

Throughout that portion of the machine in which the web is undergoingits longitudinal expansion, each successive feed roll will ordinarilyhave its ribs or fins expanded or distended to a slightly greater extentthan those of the. next preceding. feed, roll. When the.- web hasattained its maximum linear expansion, then. all the succeeding. feedrolls over which it passes will, of course, have their, ribs orfinsdistended to substantially the same extent.

Another noteworthy feature of the invention isthat different webs havingdifferent expansion characteristics may be fed through the machine inclose laterally-spaced relation to each other, yet. each of them will beproperly and efficiently fed. just as though it were the only web in themachine. This results from the fact that the rubber fins or ribs are soresilient that even maximum distortion or displacement of. a fin at onepoint in the length of a feed roll does not cause any distortion ordisplacement of. the same fin. at apoint spaced more than about of aninch away from the point: of displacement, in adirecti-on: axially ofthe roll. Hence if a plurality of. webs are run through the machine at.the same time, with lateral spacing between them as little as about oneinch, the feed roll ribs or fins can readily accommodate themselvesindividually to each web, and each web will be fed just as though noother web were present. in the machine, even through. the other webs mayhave very different expansion. characteristics.

This is well illustrated in Fig; 2', wherein three webs are shown, andit is seen that the web at left has had very little expansion during itstravel through the machine up to this point, so the fins of the feedroll are compressed to a relatively great extent under this lefthandweb. The central web has had a somewhat greater expansion, so that thefins or ribs of the feed roll are not compressed so much under this web,while the righthand web has had a still greater expansion and compressesthe ribs or fins to only a slight extent, if at all. But it is seen thatthe relatively great compression of the ribs under the lefthand web doesnot affect the position of the ribs under the center web.

This invention is especially useful in connection with a photographicprocessing machine for treating long webs of emulsion-coatedphotographic paper, the various compartments of the tanks containingdeveloping, fixing, and washing baths, in known manner. However, theinvention is not limited in its usefulness to photographic apparatus,and it may be used anywhere that webs of paper or other expansible sheetmaterial are passed through liquid baths which cause the webs to expandlongitudinally. For

example, entirely outside of the photographic field, the invention maybe employed in connection with passing paper strips through baths ofcoloring liquids, or applying successive liquid coatings of chemicals orother substances to paper strips.

Indeed, the invention is not limited to usefulness where the paper stripor other web expands upon being wetted; the same principles may beemployed in driers, where the web contracts as it is being dried, soshould be fed out of the machine at a slower rate than that at which thewet web is fed into the machine. In such a machine, the metering roll 52would have a diameter substantially equal to the maximum effectivediameter of the feeding rolls 40, instead of being close to the minimumdiameter thereof. Then the web, as it passed over the first few feedingrolls 40, would not compress the ribs or fins on these rolls, but asdrying of the web progressed, the contraction of the length of the webwould increase the tension on succeeding feeding rolls and would bendthe ribs or fins further and further over, reducing the feeding speedtoward the exit end of the machine.

The use of feed rolls having automatically variable effective diameters,to take care of ex-- pansion of the web, has already been proposed;however, the prior constructions of such variable diameter feed rollshave been impractical and unsatisfactory for one reason or another, andthe present invention provides a much more efficient and satisfactoryvariable diameter feed roll than those heretofore known.

It is seen from the foregoing disclosure that the abovementioned objectsof the invention are admirably fulfilled. It is to be understood thatthe foregoing disclosure is given by way of illustrative example only,rather than by way of limitation, and that without departing'from theinvention, the details may be varied within the scope of the appendedclaims.

What is claimed is:

1. Web feeding apparatus embodying a series of spaced parallel supportsover which a web may be run to form a multiplicity of continuing loops,certain of said supports comprising rolls the contact peripheries ofwhich are composed of a plurality of relatively thin upstandingresilient ribs each arranged obliquely to a radial line passing throughthat rib and being laterally bendable to produce substantial variationin the effective working radius of the outer end of the rib, and meansfor driving the rolls in unison at the same rotary speed.

2. Web feeding apparatus embodying a series of spaced parallel supportsover which a web may be run to form a multiplicity of continuing loops,certain of said supports comprising rolls, the contact peripheries ofwhich are composed of a plurality of laterally bendable and resilientlongitudinal ribs, of tapered cross section, thicker toward the innerends and thinner toward the outer ends of the ribs the median planes ofwhich ribs are substantially tangential to a circle struck from the axisof the roll, and means for driving the rolls in unison at the samerotary speed.

3. A flexible rubber propelling roll for web feeding apparatus thecontact periphery of which is composed of a plurality of relatively thinupstanding laterally bendable and resilient longitudinal ribs adapted torespond to varying tensions in a web loop supported thereon, each ribbeing of tapered cross section thicker toward its inner end and thinnertoward its outer end, the median planes of which ribs are approximatelytangential to a circle struck from the axis of the roll, said ribs beingreadily bendable laterally to place the outer ends thereof substantiallycloser to or farther away from the center of said roller in response tovariations in the tension of a web wrapped partially around said roll.

4. A web feeding roll having an effective diameter automaticallyvariable toa substantial extent in accordance with relatively slightvariations in the tension of a web passing over said roll, said rollcomprising a shaft, a body of soft and resilient rubber-like compositionsurrounding said shaft, and a plurality of fins spaced circumferentiallyaround said body, each fin extending longitudinally along said body andprojecting from the body in an upstanding direction oblique to a radiusextending from such fin to the center of said shaft and being relativelythin and flexible in a circumferential direction.

' JAMES F. CRAIIB.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 2,048,182 De Ybarrondo July 21,1936 2,059,979 Aiken Nov. 3, 1936 2,120,735 Debrie June 14, 19382,168,159 Hartt Aug. 1, 1939 2,175,205 Lovett Oct. 10, 1939 2,287,768Eckstein June 30, 1942

